The RJ12 port connector is located between the SD card and USB slots. The connector provides Modbus bus wires, ground potential G0, and a power supply directly connected to the G0 terminal from the power supply connector (the external devices can be powered through the RJ12 connector).
The RJ12 pins Description:
Pin1: G0 potential, (SD card side);
Pin2: RS485 - (B);
Pin3: RS485 + (A);
Pin4: G0 potential;
Pin5: G potential, directly connected to G terminal in power supply;
Pin6: G potential, directly connected to G terminal in power supply (USB side).
